1. Field of the Invention
The present invention relates to a cord tightening device of synthetic resin for tightening cords or strings on various articles such as anoraks, rucksacks, shopping bags, life jackets, and other bags and pouches having openings to be closed with cords or strings.
2. Prior Art
Known cord tightening devices typically comprise a hollow body composed of face and back plates interconnected by side walls and defining narrower and wider openings therebetween, and a slider disposed in the body and movable along a guide groove in the face plate for reciprocating movement between the narrower and wider openings, the slider including a retainer for pressing portions of a cord against the side walls, and a knob integral with the retainer and projecting through the guide groove above the face plate. Examples of such conventional cord tightening devices are shown in Japanese Patent Publication No. 48-4511, published Feb. 8, 1973 and Japanese Utility Model Publication No. 52-648, published Jan. 10, 1977. For assembling such cord tightening devices, the slider has to be forcibly pushed into the body along a groove defined in the body by elastically deforming the body in order to spread the face and back plates apart to an extent that permits such forced insertion of the slider.
Owing to the forcible insertion of the slider, the body is likely to be cracked or ruptured at the time of assembling of the cord tightening device. A similar problem also occurs when the slider is temporarily detached from the body to replace the cord with another cord having a relatively large diameter or thickness.